MockBean

Annotation that can be used to add mocks to a Spring ApplicationContext. Can be used as a class level annotation or on fields in either @Configuration classes, or test classes that are @RunWith the SpringRunner.

Mocks can be registered by type or by bean name. When registered by type, any existing single bean of a matching type (including subclasses) in the context will be replaced by the mock. When registered by name, an existing bean can be specifically targeted for replacement by a mock. In either case, if no existing bean is defined a new one will be added. Dependencies that are known to the application context but are not beans (such as those registered directly) will not be found and a mocked bean will be added to the context alongside the existing dependency.

When @MockBean is used on a field, as well as being registered in the application context, the mock will also be injected into the field. Typical usage might be:

@RunWith(SpringRunner.class)
public class ExampleTests {

    @MockBean
    private ExampleService service;

    @Autowired
    private UserOfService userOfService;

    @Test
    public void testUserOfService() {
        given(this.service.greet()).willReturn("Hello");
        String actual = this.userOfService.makeUse();
        assertEquals("Was: Hello", actual);
    }

    @Configuration
    @Import(UserOfService.class) // A @Component injected with ExampleService
    static class Config {
    }


}

@RunWith(SpringRunner.class)
public class ExampleTests {

    @MockBean
    @Qualifier("example")
    private ExampleService service;

    ...
}

This annotation is @Repeatable and may be specified multiple times when working with Java 8 or contained within an @MockBeans annotation.

See also